In recent years, energy shortage has attracted people's attention on the importance of saving energy and environmental protection. Thus, many researches focus on alternative energy and renewable energy. Solar power is found to be one of the competitive alternatives for conventional energy. The main reason is that solar cell can convert sun light into electricity without generating any polluting gas such as carbon dioxide (CO2) and can ease the phenomenon of global warming problem.
In order to improve the efficiency of solar cells, one way is to increase the illumination area of solar cells. A parabolic type concentrator having a solar cell positioned at its focus point is introduced. The parabolic type concentrator has a parabolic mirror which can focus axial collimated sun rays to its focus point. Therefore, the solar cells positioned at the focus point can receive as much sun rays as it is exposed to. However, the parabolic type concentrator requires large space and is complicated to be set up. Hence, the application of such parabolic type concentrator is limited.